1. Field of the Invention
The present invention relates to automatic scene determination using an image captured by an image pickup apparatus such as a camera or a video camera.
2. Description of the Related Art
Conventionally, a user using an image pickup apparatus such as a video camera selects a scene mode that is appropriate for a captured scene. In such a case, a user who is familiar with a video camera can determine the scene mode that is appropriate for the scene currently being captured. However, a user who is not familiar with the video camera usually captures the image using an auto mode. Further, the user becomes fully occupied with tracking an object when capturing the image, even in the case where the user becomes familiar with the video camera and can determine the appropriate scene mode. The user is thus often too busy to switch between the modes when there is a sudden change in the scene. In particular, a scene which can be effectively captured in a spotlight mode is a scene in which the main object is overexposed, and if the user does not appropriately select the spotlight mode, information about the main object becomes lost. More specifically, in a case of a scene in which a newly wedded couple enters the room in a wedding ceremony by being spotlighted in the dark, the background becomes very dark and a center portion becomes very bright. As a result, if the user selects the auto mode to capture the image, the objects in the spotlight become overexposed.
Further, recent image pickup apparatuses have been capable of performing various types of automatic scene detection due to an improvement in the performance of an image processing integrated chip (IC) or a central processing unit (CPU). For example, Japanese Patent Application Laid-Open No. 05-056331 discusses an image pickup apparatus that detects the captured scene from a histogram and changes a weighting ratio in a light metering frame according to the detected scene. The main object thus becomes appropriately exposed in a scene in which the histogram is divided into a dark portion and a bright portion, such as the spotlight scene.
However, the image pickup apparatus discussed in Japanese Patent Application Laid-Open No. 05-056331 requires the user to determine the scene and switch the mode. Since the user is occupied with tracking the object or adjusting an angle of view, the user is unable to determine the scene and thus capture the image in the appropriate mode. Further, the camera discussed in Japanese Patent Application Laid-Open No. 05-056331 does not detect luminance distribution in a screen even when it automatically determines the scene, so that if the object is a black and white checkerboard pattern, the image pickup apparatus cannot correctly determine whether the scene is the spotlight scene. The image pickup apparatus thus performs light metering by focusing on the bright portion even in a normal scene which is not the spotlight scene. An undesirable image capturing result is thus acquired, in which the main object becomes underexposed.
The present invention is directed to automatically performing spot light scene determination with higher accuracy.